Hone



July 13, 1948. w. F. MITCHELL HONE Filed Nov. 19, 1945 l@ @N QN MN RN www Patented July 13, 1948 anni HONE

Wallace F. Mitchell, Chicago, Ill., assignor to Ammco Tools, Inc., a corporation of Illinois Application November 19, 1945, Serial No. 629,375

14 Claims. (Cl. 51-184.3)

This invention relates to a device for honing small bores and particularly bores 3A" and less in diameter. Of course, it may be utilized for honing larger bores, but the problem it solves is one that has heretofore existed with respect to small bores of the size mentioned.

It is well known that accuracy in the honing of small bores with respect to roundness and size, is directly proportionate to the number of honing stones employed. At the same time, the device supporting and driving the honing stones must be sturdy and have sufficient rigidity to withstand the power requirements of the stones. Also, an increased number of stones insures faster grinding, but this is accomplishable only if the tool has suflicient rigidity and sturdinessto take care of the power requirements to effect the necessary operation of the tool for this work.

Heretofore, in order to meet these requirements it has been necessary to provide tools which are ratherexpensive and which require considerable care and skill in manipulating rto effect the desired accuracy; however, at the same time, sacriiicing speed in honing. These conditions have existed in prior tools due to thefact that for honing bores and less in diameter it has been necessary to resort in some cases to one, and in most cases to not more than two stones, especially with respect to bores under 1%. In some instances hones for taking care of bores 3A have employed three stones, but in all such cases in order to get the desired rigidity to provide a practical tool, an expensive` construction has been resorted to, thereby tending to greatly limit the use and availability of such tools.

The object of this invention is to provide an improved device for honing small bores, and particularly one well adapted for honingl bores 3A." or less in diameter, and which is free of the objections of prior tools, and vwhich is adapted to accomplish all the foregoing desired advantages in a highly eficient manner. More particularly, my invention yprovides a tool which embodies means for supporting three or more stones, so as to get the desired accuracy above noted.

It further provides means for supporting thesestones in such a way that they are carried and driven in a so-called rigid way whereby the tool is suflciently sturdy and rigid to withstand the stress imposed by power drive means'in honing the bore.

It further provides an arrangement whereby` the honing operation may be carried out more quickly due to the availability of a greater number of stones.

It also provides accurate and improved means for expanding the stones during operation into uniform and balanced grinding engagement with thesurface of the bore being honed.

It also provides a tool with all of these characteristics which is very simple in construction, but which is highly efficient in operation, and which is adapted for long life use with a minimum of care.

It provides a tool which may be handled by an inexperienced operator and still accomplish accurate honing operations.

More particularly, the foregoing advantages are attained by providing a rotatable body which is split longitudinally providing expansible sections, which body supports a resilient sleeve which is expansible and contractable, and which, in turn, supports a plurality of stones on its outer surface. In other words, the body member not only serves as an expansible member but it is the drive member and the support for the sleeve carrying the stones. In this way, the structure greatly simplified while attaining all of the advantages above set forth and which are required for fast grinding and accuracy, etc.

The invention further consists in the several features hereinafter set forth and more particularly defined by claims at the conclusion hereof.

In the drawings:

Figure 1 is a plan'vew of a hone embodying the invention connectable for operation by drive and feed connections, parts of which are shown broken away and in section, with any suitable power driven honing machine;

Fig. 2 is a vertical sectional view through the hone, parts being broken away and the stones being in a retracted position;

Fig. 3 is a view similar to Fig. 2, with the stones shown in expanded position in the bore. of the work being operated upon;

Fig. 4 is a detailed cross-sectional view taken on line 4 4 of Fig. 2;

Fig. 5 is a detailed cross-sectional view taken on the line 5-5 of Fig. 3;

Fig. 6 is a detailed sectional view similar to Fig. 4 showing certain modications.

Referring to the drawings, this tool comprises a drive adapter 'l which may constitute a part of any suitable power driving means such, for example, as a honing machine. The drive adapter 'l rigidly carries a hollow drive shank 8 which externally supports a centering cone 9 adapted to engage one end of the bore to be honed, for centering the tool therein, as will be well understood. The forward end of the drive shank 8 is internally threaded for the reception of the threaded shank iii of a tool body or mandrel ii, having a flange-like head l2 adapted to :iirmly .seat against the front end of the drive shank 2i so that the body drive shank and drive adapter constitute one rigid unit when assembled.

The body member I I is provided with four parallel longitudinal slots i3 extending from the flange I2 to the forward end of the body to provide an expansib-le mandrel. The body II is also hollow, being provided internally at an intermediate portion thereof with an inwardly extending annular ridge which by the slotting of the body is divided into a plurality of expanding cam elements Ill for expanding the mandrel. The outer surface of the body il is provided with a pair of longitudinally spaced, annular split ridge portions I5 and it which are equally spaced longitudinally from the cam elements lli. VThe pur pose of the ridge portions I5 and I5 is to provide a pair of circumferential or parallel supports for an expansible stone carrying sleeve Il which is formed of spring metal so that it may be expanded and contracted in a manner which will be explained later.

The sleeve I'I is a split sleeve, one of whose edges I8 at the slit is bent inwardly to engage a side I9 of one of the slots I3 in. the body member to form a drive connection therewith. Abrau sive stones 20 are mounted on the sleeve in any suitable manner, as by sets of spaced tongues 2i struck up from the bodyof the sleeve as shown in Figs. 1, 4, and 5 and engaging opposite sides of the stones or by pressing out stone receiving pockets 22 in the body of the sleeve. In both instances the stones may be held by a suitable cement such as indicated at 23. The sleeve Il, being a relatively inexpensive member as compared to the cost of the stones, may be thrown away when "the stones 20 have been used up.

The forward end of the mandrel II is externally threaded for reception of a head Inut 24 which with the iiange l2 denes the longitudinal position of sleeve I 'i upon the mandrel il and limits any longitudinal shifting movement of the .2

sleeve thereon. The head nut 2d is provided with an internal shoulder 25 adapted to seat against the extreme forward end of the mandrel ll and thereby position the forward face 26 of the nut relative to the forward end of the sleeve Il. This relationship is such that the front face 26 of the nut 24 does not abut against the front end of the sleeve Il, there being slight space therebetween to permit of radial expansion and contraction movements of the sleeve. be out hereinafter, when the mandrel I I is expanded, it necessarily contracts in length, tending to Apull the face 265 of the nut 2'4 to'ward the front end of the sleeve I`1, and unless otherwise prevented this action would paralyze or freeze the sleeve I 'l between the ilange i2 and the face 2li of the nut. However, to prevent 'this and to maintain the desired clearance between the sleeve l1, nut 2li and flange I2, the forward face 26 of the nut 24 is cut away at an angle sufcient to maintain the necessary space relationship as the mandrel il is expanded and the sleeve I1 necessarily moved outwardly in the expanding operation. This angle is likewise provided on the forward face of the flange I2, the arrangement being such as will be obvious from the drawing that as the ends of the sleeve move outwardly, they lie adjacent the increased spacing provided by the angle, so that even though the nut 2i. and the flange l2 are brought closer to- Also, as will lil gether by the expansion of the body, the clearance will still be maintained.

The nut 24 is further provided with an inner concentric threaded plug 2l which passes through the bore of the front end of the split body II holding the body sections in true locked relation to the nut 24 when the body is bowed, as shown in the drawing. If this were not provided, the bowing action would tend to release the front threaded end of the body from the nut and render the nut inoperative for its intended purpose.

The mandrel Il is expanded by an adjustable wedge member 28 extending through the drive adapter l, hollow drive shank ii, and into the mandrel II. The front end 29 of this member is conically tapered providing a wedge cooperating with the expanding elements lll in such a way that When the member 28 is moved forwardly, the expanding elements are engaged therewith to expand the body sections between the slots I3 outwardly, as shown inthe drawing. This expansion takes place by a springing apart of the body sections which tends lto shorten the body, as above explained.

The shank IU of the body which extends a substantial distance into the forward end of the drive shank 8, provides in effect an elongate bearing for the front end of the wedge member 28. A slidable clearance is maintained between this shank 8 and the wedge member and is of such length that the wedge 28 is maintained in concentric relation with the expanding elements I4 without a cooking action during the expanding movements as afforded by the machine driving the tool.

The adjustable wedge member Y23 is formed in two sections, the rear section 30 tting slidably within the rear end of the drive shank 8 and the forward section Y3l' being separate and fastened to the rear section as by a pin 32. The forward section 3| is of reduced diameter providing a clearance for a spring 33 which is carried under compression, tending at all times to move the wedge member to a release position. Expansion of the hone is accomplished against the action of this spring. Also, this sectional `arrangement of the wedge 28 is employed because it is desirable that the forward section 3l which engages the expansible elements I4 be formed of tool steel,

i or of that metal which will withstand a tendency to wear during the adjusting operation. It is not necessary that expensive material of this character be used throughout the length of the adjustable wedge, so that the sectional arrangement enables the rear end to be made of cheaper material than the forward end, thereby reducing cost without impairing eiciency in any way. Furthermore, this arrangement eliminates turning down operations and insures the accurate formation of the conical end 29.

With `this construction the ran-ge of expansion of the mandrel il is relatively large so that a relatively wide range of diameters may be iinish honed with the stone supporting sleeve il'. However, in use, the stones, of course, wear, and when they have worn down to such an extent that they have lost their usefulness, the sleeve l'I with the worn stones is removed by screwing out the plug 2l and unscrewing the nut 24 from the mandrel li and repla-cing the worn stone carrying memn ber with a similar new element and screwing :back the nut 24 and the plug 21.

It will, of course, be understood lthat the 'honing operation is accomplished by the rotation of the hone through the drive of the mandrel Il from the honing machine, the operator usually sliding the work back and forth alongr the hone vduring this operation, and during this operation vthrough 'the action of the honing machin-e pressing outwardly on the wedge member Z8 to expand the hone to the desired -position for causing the stones to hone the bore in the work W (Fig. 5) to the desired diameter, the stones on the completion of the work being retracted by the contra-ction of the sleeve ll upon release `of the wedge connection between the wedge member 28 and the cam elements Ill of the mandrel l l.

I desire it to be understood that this invention is not to .be limited to any particular form or arrangement of .parts except insofar as such limitations are included in the claims.

I claim:

1. In a honing device, .the combination of a rotatable tubular drive shaft, an expansible mandrel connected to said drive shaft, an ex'pansible sleeve mounted on said mandrel, a plurality of honing stones carried by said sleeve, and means including a wedge memlber slidable longitudinally in said drive shaft and engageable with said mandrel to expand the same and said sleeve to move said stones radially outwardly.

2. In a honing devi-ce, the combination of a hollow mandrel slotted longitudinally to provide expansible sections, said sections having longitudinally spaced circumferential supporting portions, a split spring metal sleeve mounted at spaced point-s on said supporting portions, honing stones carried by said sleeve, and adjustable means within said mandrel for engaging said expansible sections to move the same outwardly and thereby through said sleeve move said stones radially outwardly.

3. In a honing device, the combination of an expansible mandrel adapted for connection with a rotatable drive shaft and including longitudinally split sections provided with exterior longitudinally spaced hone supporting portions, a hone comprising a split spring metal. sleeve mounted on said supporting portions and honing stones carried by said sleeve, said sleeve having a depending tongue engageable with a side of a slot of one of said expansible sections of said mandrel for driving said hone from said mandrel, and means for expanding said sections and said sleeve to move .the stones radially outwardly.

4. In a honing device, the combination of an expansible drive mandrel having an angularly l inclined shoulder portion at its inner end and a threaded portion at its outer end, a nut having an angularly inclined inner face portion mounted on said threaded portion, said angularly inclined shoulder and said inclined inner face disposed in outwardly d-iverging relationship, said mandrel being slotted longitudinally to provide a plurality of expansible sections, exterior longitudinally spaced circumferential ribs on said mandrel, a split sleeve member mounted on said mandrel and positioned within the limits of said space in any radial position of said sleeve relative to said mandrel, a plurality of abrading stones carried by said sleeve, and means for expanding said mandrel to in turn expand said sleeve to move said stones on said sleeve radially outwardly.

5. In a honing device, the combina-tion of an expansible drive man-drei having an angularly inclined shoulder portion at its inner end, a threaded portion at its outer end, and longitudinally extending slots extending from the outer end thereof to said shouldered portion, a nut having an outwardly inclined inner face in threaded engagement with the .threaded end of said mandrel and provided with a centrally disposed bore and a screw .plug in threaded engagement with said bore and closely associated with the inner bore of said mandrel to prevent appreciable spreading movement of the outer end of said mandrel while in an expanded condition, Isaid angularly inclined shoulder and said face disposed in outwardly diverging relationship, and a hone having an expansible sleeve portion mounted 'on said mandrel and positioned within the limits vof said space in any radial position of said sleeve relative to said mandrel, a plurality of brad-ing stones carried by said sleeve, an-d means for expanding said mandrel and sleeve to move said stones on said sleeve radially outwardly.

6. yIn a h-oning device, the ycombination of a hollow drive mandrel slotted to provide expansiblc sections and which sections are provided intermediate their length with inwardly extending cam portions, said mandrel also having spaced circumferential supports on opposite sides of said inwardly extending' por-tions and substantially equally spaced relative thereto, a hone compris'- ing a split spring metal sleeve mounted on said supporting portion-s, and stones carried by said sleeve, and a wedge member'lengthwise movable to engage said inwardly extending camy portions of said mandrel section-s to expand `the same and thus 'che sleeve to move said stones radiallyoutwardly.

'7. In a honing device, a mandrel symmetrically expansi-ble radially, a split spring metal sleeve mounted on said mandrel drive-connected and expansible therewith lthroughout the :circumference, said sleeve having its exterior surface deformed to provide a plurality of circumferentially spaced abrading stone supporting means, and ahrading stones .secured to said abrading stone supporting means.

8. In a honing device, a mandrel symmetrically expansible radially, a split spring metal sleeve expansible substantially uniformly throughout its circumference by said mandrel having an inwardly extending tongue drive-connected with said mandrel and a plurality of circumferentially spaced sets of tongues struck up from its periphery, and honing stones mounted between said spaced sets of tongues.

9. In a honing device, a mandrel symmetrically expansible radially, a split spring metal sleeve mounted on said mandrel drive-connected and expansible therewith throughout its circumference, said sleeve having its exterior surface depressed to form a plurality of longitudinally extending, circumferentially spaced stone receiving channels therein, and abrading stones secured in said channels.

10. A honing device comprising a hollow mandrel split lengthwise at a plurality of circumferentially spaced points providing radially expansible sections, an annular series of expanding elements Within said mandrel, .one on each of said sections, a pair of longitudinally spaced annular sets of sleeve supporting elements on the exterior of said mandrel, said series of expanding elements being disposed between said sets of supporting elements, a split sleeve mounted on said mandrel in seated relation to said sleeve supporting elements, an expander member shiftable Within said mandrel to engage said expanding elements to expand said mandrel and in turn said sleeve, and abrading stones carried exteriorly by said sleeve.

11. A honing device comprising a mandrel having a hollow expansible body, means movable relative to said body for expanding and contract-- ing it, an expansible sleeve mounted on said. body for support and adapted to be expanded and contracted thereby, means drive-connecting said sleeve to said body so that they may be rotated as a unit, whereby said body serves to support, diVe and eXDarld said sleeve, and abr-ading stones mounted on said sleeve at exterior circumferentially spaced points therearound.

12. A honing device comprising a mandrel having a hollow body expansible and contractible intermediate its ends, expander elements within said body on the expansible part thereof, supportn ing elements 4on the exterior oi said body on the expansible part thereof and on opposite sides 1ongitudinally displace-d from said expander elements, an expansible sleeve mounted upon said mandrel and seated on said supporting elements, means shiftable within said mandrel and engageable with said expander elements to expand said body and in turn said sleeve, and abrading stones carried externally by said sleeve in circumferentially spaced relation therearound.

13. A honing devi-ce comprising a mandrel haV- ing an expansible body portion, retainer heads at the opposite ends of said expansible body and having their facing surfaces cut away at an angle providing annular outwardly diverging faces therebetween, an expansible sleeve mounted on said expansible body between said faces with its opposite ends disposed in juxtaposition to the faces of said retainer heads, means within said body for expanding it and in turn said sleeve, and abrading stones carried exteriorly by said sleeve.

i4. A honing device comprising a mandrel having an expansible body porti-on, sleeve retainer heads at the opposite ends of said expansible body, the facing surfaces oi said heads being cut away at an angle so as to provide a space therebetween progressively increasing in width from the inner toward the outer portions of the faces of said heads, an expansible sleeve mounted on said expansible body and confined endwise by said heads in free expanding condition, means for expanding said body and in turn said sleeve, and abrading stones carried by said sleeve, the arrangement being such that said sleeve may freely be expanded to engage' said stones with the surface 'to be treated notwithstanding any shortening of the space between said heads as said body is expanded.

WALLACE MITCHELL.

REFERENCES CITED The following references are of record in the file of patent:

'NTED STATES PATENTS Number Name Date 2,044,474 Groetchen June 16, 1936 2,146,195 Schultz Feb. 7, 1939 2,411,545 Kline Nov. 26, 1945 

